Conventionally, a backlight illumination using a cold cathode fluorescent tube is widely used for a liquid crystal display apparatus using a liquid crystal display panel. Further, in recent years, a backlight illumination using light emitting diodes (LED elements) of three colors, which emit red, green, and blue lights, respectively, has been developed so as to reproduce natural color tone with enhanced brightness.
In particular, for a relatively small-scale backlight illumination used when an enhanced brightness is unnecessary, a lateral light source type planar illumination apparatus of a so-called edge light type is used in which a light from a light source is incident on a side surface (incidence plane) of a light guide plate, and the light is emitted from one main surface (emission surface) of the light guide plate so as to perform illumination. On the other hand, for a large-scale backlight illumination used when a high brightness is needed, a direct illumination apparatus having cathode fluorescent tubes or LED elements arranged in a planar form is used.
In the future, a demand for a liquid crystal display apparatus which has a thin large screen used for, for example, a wall-hanging television may be increased. However, reduction in thickness of the direct illumination apparatus is more difficult than reduction in thickness of the edge light type illumination apparatus. On the other hand, the edge light type illumination apparatus having an increased screen size may not ensure a sufficient brightness.
In order to realize a liquid crystal display apparatus having a thin and large screen, a study for an edge light type planar illumination apparatus using, as a light source, LED elements each having a brightness enhanced has commenced. For example, a type disclosed in Patent Document 1 has been suggested.
In a case where LED elements are used as a light source for the edge light type illumination apparatus, when a plurality of LED elements are arranged in line on a side surface of a light guide plate, power consumption may be increased and/or generation of heat may be increased. Therefore, it is disclosed in Patent Document 1 that, as shown in FIG. 18, a bar-type light guide element 400 is disposed adjacent to the side surface of a light guide plate 500, and two LED elements 300 are disposed on both ends of the bar-type light guide element 400. In this configuration, lights from the two LED elements 300 are subjected to multiple reflection in the bar-type light guide element 400, so as to obtain a uniform light amount distribution, and are then incident on the side surface of the light guide plate 500 from the side surface of the bar-type light guide element 400 after the uniform light a mount distribution is obtained.    Patent Document 1: Japanese Laid-Open Patent Publication No. 11-271767